Modeling of quasi-2D experiments on fine-scale dual-phase steel deformation mechanisms

The deformation of dual-phase steel microstructures, consisting of ferrite and martensite phases, is investigated through a recently developed high-resolution integrated experimental–numerical framework. Subsurface microstructural features, which can significantly influence surface deformation patterns, cannot be measured in traditional experimental techniques, and thus cannot be incorporated into simulations. The approach adopted in this paper eliminates subsurface microstructural changes, facilitating rigorous comparison between simulations and experiments. The framework is complemented by fine scale crystal plasticity models accounting for sub-grain heterogeneity in ferrite and substructure boundary sliding in martensite. An exceptional agreement between simulations and experiments is obtained, through which important aspects of deformation features in dual-phase steel microstructures are revealed. A kink band formation in martensite is observed, caused by the highly anisotropic plastic behavior. Furthermore, slip traces in martensite are aligned with {557}_γ habit planes. Finally, severe strain localizations in martensite are seen. This demonstrates that martensite can undergo ductile deformation for favorable habit plane orientations.